This second bucket lift-pump arrangement uses an on-axis piston check above a foot check. The animation keeps the entered bore and stroke on one fixed drawing scale and shows the complementary valve sequence.
Lift Pump Form 2 Interactive Calculator
Estimate swept volume, efficiency-adjusted delivery, static suction-column pressure drop and the ideal water power associated with that column. The results are first-order water quantities, not a pump or installation rating.
Equation Used
- Water density is 1000 kg/m3 and g is 9.81 m/s2.
- Bore and stroke describe the ideal swept cylinder volume.
- Volumetric efficiency is a declared aggregate delivery allowance; cavitation margin and mechanical efficiency are excluded.
The animation makes one complete upstroke-and-downstroke cycle at the entered cycle rate. Flow and water-column power remain ideal calculations with the entered delivery allowance.
Complementary piston and foot checks
On the upstroke, the piston check closes and the foot check opens. Water enters below the rising piston while the water already above it moves toward the spout. On the downstroke, the foot check closes and the piston check opens so water transfers through the descending piston.
The drawing is a sectioned schematic. Its valve timing and proportions are schematic rather than manufacturing data.
Where this pump principle is used
The piston valve and foot valve are characteristic of single-acting bucket pumps. They can be operated by a hand lever or by a reciprocating drive, with cylinder placement chosen for the water source.
This drawing shows the valve cycle rather than a particular commercial pump. Suction-depth limits and component details depend on the pump and its installation. A surface-mounted suction pump and a submerged borehole cylinder have different installation constraints.
Displacement, delivery and water-column power
The static suction-column pressure drop is rho gh. Multiplying that pressure by delivered flow gives the ideal hydraulic power associated only with the suction column: Ph = rho ghQ. It is not motor or handle input power.
Worked arithmetic example
With an 80 mm bore and 125 mm stroke, ideal swept volume is 0.628 L per cycle. At 30 cycles per minute and an entered volumetric efficiency of 85%, delivered flow is 16.0 L/min. A 6 m static water column corresponds to 58.9 kPa and 15.7 W of ideal delivered water-column power.
The entered efficiency is an aggregate allowance. These arithmetic results do not establish valve timing, cavitation margin, required operator force, pipe losses or a safe installation.
What this model can and cannot compare
Bore, stroke, cycle rate and entered volumetric efficiency determine the displayed displacement and delivery. Increasing any of them increases the arithmetic flow result, but the calculator does not predict how efficiency changes with speed or diagnose a particular pump.
Actual performance also depends on valve dynamics, leakage, suction-line condition, acceleration head, friction loss, atmospheric pressure and vapor pressure. Use measured data or manufacturer guidance for a real installation.
Lift-pump model questions
Does the calculator predict efficiency at a selected speed?
No. Volumetric efficiency is an independent user input; the page does not supply a speed-to-efficiency curve.
Does the static pressure result set a universal suction limit?
No. It is only rho gh for the entered water column. Cavitation and available suction margin require additional site data and losses.
Does ideal water power equal handle or motor power?
No. It excludes mechanical losses and all input-side inefficiencies.
Mechanism reference
- FAO, Water Lifting Devices: describes the bucket-pump piston valve, foot valve and piston-pump discharge relationship.
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